Steam Turbine

STEAM TURBINE

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An Introduction to Steam Turbine at Shuweihat S1 through  An Overview of the Steam Turbine and its subsystems  Basic logics of some of the systems – made easy

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What will we do? Take a look at  Technical Data, pictures and section drawings - MAA  Lube Oil System - MAV  Control Oil System - MAX  Gland Steam System - MAW  Turbine Drain System – MAL Go around the ST 3 12/04/09

What we will cover in a session sometime later  TSE

and Margins  STG Start Up and Shut Down  STG controller  Detailed discussion on Protections  Lub Oil Purification Unit

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Simple Rankine Cycle

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2

to 3: Isobaric heat rejection (Condenser)  3 to 4: Isentropic compression (Pump)  4 to 1: Isobaric heat supply (Boiler)  1 to 2: Isentropic expansion (Steam turbine )

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Name Plate Details Type- M30-40

Order No - 10445

Year of Manufacture -2003

Steam Press. – 76.5 Bar

Steam Temp. – 560 ºC

Speed – 50 rps

Rated Capacity – 251.35 MW

Exhaust Steam Pressure – 2.8 Bar 8 12/04/09

Steam Parameter Limits  Steam

Flow – 325.44 kg/s  Steam Pressures in Bar Absolute Nominal

Long Term

Short Term

Main Steam

76.5

85.7

99.5*

Before 1st Stage

75.5

81.5

81.5

Exhaust Steam

2.23

5.0

7.0

Long Term – Upper limit with no time restriction Short Term – Permissible instantaneous value with cumulative duration not more than 12 hours in a year. * - Set the safety valve so as not to exceed this value 9 12/04/09

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ST Speed Sensors -Total 6

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Turbine Oil Specs  Mineral

or Synthetic oil of viscosity class ISO VG 32 or ISO VG 46 (DIN 51 519)  Capable of withstanding 120 ºC in bearings and 80 ºC in the oil tank without physical or chemical degradation.  Hydraulic Oil – ISO-L-HM46 (DIN 51524-HLP46) capable of withstanding 70 ºC. 16 12/04/09

Hydro Safe ISO VG 32  





Non-Toxic - Biodegradable - Environmentally Friendly Antiwear - Hydraulic Oil Hydro Safe ISO VG 32 is a vegetable based hydraulic fluid formulated to meet the demand for biodegradable hydraulic oils. It is designed to minimize environmental impact and have low environmental persistance. Hydro Safe ISO VG 32 offers excellent antiwear performance in a wide array of hydraulic components, and can be used as a superior replacement for conventional petroleum oil. It exhibits good thermal and oxidative properties when compared to other vegetable-derived products. Formulated from canola oil, and containing biodegradable, non-toxic chemical additives. Its high vicosity index (VI) allows outdoor operations in winter and summer without the need for fluid changes or equipment modifications. Viscosity Index ASTM D-567, ASA Z11.45 is an empirical number indicating the rate of change in viscosity of an oil within a given temperature range. A low viscosity index signifies a relatively large change in viscosity with temperature change, while a high viscosity index shows a relatively small change in vicosity with temperature change. Viscosity Index cannot be used to measure any other quality of an oil. The fluid is totally biodegradable, and exceeds the government criteria of being "readily biodegradable." Readily biodegradable is defined as an attribute of products that have a natural ability to biodgrade quickly and completely. Once the fluid is leaked into the ground, it has the ability of substance to be digested or consumed by naturally occurring microorganisms present in water, air, and soil systems. Complete biodegradability is the conversion of a substance to carbon dioxide and water.

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Steam Purity – Why ?  Impurities

can cause damage to turbine components by - corrosion, stress corrosion, corrosion fatigue, erosioncorrosion.  Deposition can cause - thermodynamic losses, lower efficiency, upsetting of pressure distributions, clogging of seals and clearances 18 12/04/09

Values recommended for continuous operation Parameter

Unit

Normal Value

ACC @ 25 ºC

μS/cm

< 0.2

Achievable Value 0.1

Na

μg/kg

<5

2

Silica

μg/kg

< 10

5

Total Iron

μg/kg

< 20

5

Total Copper

μg/kg

<2

1

Mass weighted averaging for multiple sources. i.e. if A – conductivity A = ∑Mi * Ai / ∑Mi

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Limit Values for Start Up and cases of deviation from values recommended for continuous operation. Parameter

Unit

Action Level Action Level 2Action Level 3 Action Level 4 1

ACC @ 25 ºC

μS/cm

Na

μg/kg

≥ 5 < 10

Silica

μg/kg

Total Iron

≥ 0.2 < 0.35 ≥ 0.35 < 0. 5

≥ 0.5 < 1.0

≥ 1.0

≥ 10 < 15

≥ 15 < 20

≥ 20

≥ 10 < 20

≥ 20 < 40

≥ 40 < 50

≥ 50

μg/kg

≥ 20 < 30

≥ 30 < 40

≥ 40 < 50

≥ 50

Total Copper

μg/kg

≥2<5

≥5<8

≥ 8 < 10

≥ 10

Hours per event allowable

h

≤ 100

≤ 24

≤4

0

Cumulative time per year

h/a

≤ 2000

≤ 500

≤ 80

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Output Limit During Valve Testing  While

testing the Main Steam Stop and Control Valves with Automatic Turbine Tester, the Turbine output should be limited to 80%

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HP Steam from Gland steam exhauster

2 Inlet Pipes ESV 1 Safety Valve

ESV & CV Drain Valves CV 1

Butterfly Flap

CV 2

ESV 2 Turbine Drain Valve

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TLRI 115/52 16.5 + 5% KV, 10462 A 299 MVA, COSØ – 0.85 COLD AIR – 41 ºC

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Turbine Stop & Control Valves 2

Stop and Control Valves each  Stop and CV combined in a common body with stems arranged at right angles  Stop Valve – Single seat valve with integral pilot disk. Hydraulic actuation against spring force – will close in case of power failure to solenoid  CV – Tubular disk with relieving holes. Hydraulic actuation against spring force. 28 12/04/09

Function – ESV – MAA11/12AA051  Rapid

and reliable interruption of Steam Supply to the turbine in case of activation of protection.  To allow admission of steam for warm up of the CV during cold start

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Function – CV – MAA12/22AA151  Rapid

interruption of Steam Supply to the turbine in case of activation of protection  Allow admission of steam into turbine for warm up during start.  Control the speed gradient during run up to Nominal speed  Control the load of the steam turbine when synchronised 30 12/04/09

Example (Not at S1)

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ST ESV

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ST CV

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TURBINE EXHAUST AND SAFETY VALVES

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HP Steam from 2 Inlet Pipes

Start up / Safety Valve

•

Steam Press Check Device

3 pressure switches – 1 of 3 actuation • 2 of 3 for turbine trip through TTS ESV • Cyclic self test - If test1 not OK, test stop and 1of 2 mode. • & CV ESV Draincheck of device allowed Manual Valves during turbine load operation but CV 1 load < 80%

Gland steam exhauster

ST Exhaust Valve – NAA50 AA001 • ST Butterfly valve––NAA50 STExhaust ExhaustValve Valve NAA50AA001 AA001 ••• Hydraulic actuator with closing Operation Start Test spring Open – dp > 100 mbar and •• Automatic Start by SGC SLC on valves NAA50 • 2 trip solenoid ST, XS51 • Close ST tripsupply or Safety Functions AA013/014 ––power from • Manual test by start Valve open •Safety Valve – Protects ST exhaust from too high pressure (4.0 bar) CV 2 Turbine trip system • command from actuated OM Fire Protection – •Dump Valve – Opens when ST trips, to limit blading stress • Pilot valve NAA50AA011 for part hydraulic system is switched (recommended once in 6 •Globe Start-up valve valve – 10% – Protects rated blading MS flowfrom too high temperature caused lift testweeks) off. •Hydraulic by windageoperated Safety Valve with ESV 2 During • Closing time –ST2s,maintenance Opening time – – •• Pilot valve On – Valve • start up (Unitdevice CB Off and speed > 47.5 Hz and Exhaust steam e.g. pressure check can be locked in close 150s closes slowly, 82% Turbine Drain Valve position and seal airlimit can be2 •Control steam Prot high) fluidtemp supply from MAX01 • Control fluid by extra unit with switch, switches off pilot provided between the 2 ring •system Vent Valve – Opens during all starts at SGC ST step 21 and closes pumpsvalve + a manual pump for seats (80% second limit •Opening at step 22 time (& speed – 2s > 9 Hz) – commissioning modification to vent out emergency switch) •Closing air in the time exhaust – 15s section. • Task - To separate ST exhaust 36 •Has 4 functions from Process steam header 12/04/09 Butterfly Flap

Lube Oil System - MAV  Safe

Oil Supply to Bearings  Jacking up shaft at low speeds  Driving the hydraulic turning device  Avoid escape of oil vapours from the bearings and the oil tank  Oil cooling  Oil Purification  Special Op mode during Fire Protn 37 12/04/09

Main Components  Lub

Oil Tank MAV10BB001

2

x 100% LOPs (~ 5.5 Bar) MAV21AP021/022  1 x 100% EOP (~ 2.5 Bar) MAV24AP001 2 x 100% Lift Oil Pps (~ 160 Bar) MAV24AP001  2 x 100% Vapour Extractor fans MAV82AN001/2 

2

x 100% Lub Oil Coolers  2 x 100% Lub Oil Filters  Thermostatic Temperature CV  Oil Purification Unit

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10MAV

2v3=42FP016 If 1v3 < 2.5 Bar – Warning If 2v3 < 2.3 Bar & Speed>0.25 Hz-Turbine Trip

10CT001 •Should be > 10 Deg C to enable SGC Oil Supply •SGC Oil Supply maintains Oil Temperature 42CT001 between •High Deg Warning > 57 Deg C 25-35 C in at Shutdown •Tempby>30 Steps Starting Deg C& - SGC ST stopping Release atPre-selected step 21 LO Pump

If DP>0.9 Bar -Alarm

1. 2. 3.

Auto Pump Changeover If 42CP019<2.5 OR 21CP001<4.8 Bar then Auto Changeover Electrical fault of Running Pump – ACO EOP will start in any Change over command

2v3-10FL021 L = 1v3 < 1050 Alarm LL= 2v3 < 1000 ST Trip & Emg Operation/Fire Protection Activated H= 1v3 >1150 Alarm HH=2v3 >1200 ST Trip SGC Turbine Oil supply Start Enable Condition Oil Level 1170 – 1260 mm

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35CP001 If Press < 125 Bar and Running Pump Discharge Press < 125 Bar - Press Low Alarm Also Command for AUTO CHANGEOVER

31CP001 If Press> 180 Bar High Warning If < 125 Bar – Low Alarm

If Oil Supply Emergency Operation is triggered by following reasons

10MAV

1) Fire Protection Manual Switch is activated or detected OR CCR Push Button 2 Tank LOW LOW Level Then following will be executed 1)CF Supply Protection OFF 2)Turbine Trip 3)GC Oil Supply –Manual 4)SGC Turbine OiL Supply –OFF 5)Main LO Pumps35CT001 –Prot OFF & SLC -OFF RESET required before Oil •Temp > 65 is –Warning Supply •Temp > 70 can Degbe C RESTARTED & Speed < 0.15 Hz & TM HPS < 100 Deg C then Temp TOO If DP>4.2 Bar High Alarm & Lift Oil -Alarm Pump OFF

6)EOP OFF Enabled 7)SGC Check Oil Pumps-OFF 8)Lift Oil Pumps OFF & SLC OFF 9)Oil Maint System OFF 10)Eop Protection ON 11)Turning Gear OFF 82CP001 Press> -5 mBar – Auto Changeover

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HP side Bearing & HydroMotor

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Thrust Pads

Journal Bearing

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Outer Wheel is connected to HYDRO Motor Inner Wheel is connected to ST shaft ST Shaft

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HYDRO Motor Working Principle

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CLUTCH Hydro motor & ST Shaft

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Manual Turning Gear Mechanism

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Control Fluid System MAX  Supply

the ST ESVs, CVs and Safety Valve actuators with high pressure control fluid (160 Bar)  Fast closing/opening of valves when Trip signal actuated.  Transmission of electrical signals from turbine controller into hydraulic signals for fast and accurate positioning of CVs 48 12/04/09

Main Components  Control

fluid tank MAX01BB001  2 x 100% control fluid pps MAX01AP001/002  2 Hydraulic accumulators MAX01BB011/012  2 filters downstream of each pump MAX01AT011/012  1 Circulating oil pump MAX01AP011  1 Control fluid cooler MAX01AC011  Fine mesh filter d/s of cooler MAX01AT013 49 12/04/09

CT901-2v3 Low Low < 5 Deg 2v3 Level SwitchesC - Both Pumps Protection OFF 1) Low Temp > 15 2) Low LowDeg C Enables SGC Turbine Valves 3) Low Operation Low Any 2v3 activates ST Protection and SGC High > 70Valves Deg Auto Shutdown and Turbine Pumps Prot OFF High High > 85 Deg C then ST Auto Shutdown by SGC Turbine Valves SD and Start Device- Set Point LOWERING

If CF Supply Emergency Operation is triggered by following reasons Auto Changeover Press < 150 for 100 Secs then OR 1) Fire Protection Manual Switch is activated orIfdetected < 115 Bar then 2) Oil Supply Emg Operaion is triggered AUTOCHANGEOVER Command If Discharge Header Press > 150 Bar & 01CP003 any for one110secs Pump inthen service Then following will be executed •If Press < 150 Bar If Both Pumps Discharge < 105 Bar 1)CF Supply Protection OFF OR then ST Prot TRIP 2)Turbine Trip •If Press < 110 Bar then Low Press 3)CF Circulation Pump OFF Alarm 4)SGC Turbine Valves –Auto Shutdown 5)CF Pumps –Prot OFF & SLC –OFF 6)Both ESVs Prot OFF

CONTROL FLUID SYSTEM (MAX )

If any two Transmitters deviation > 5 then FAULT is Generated If DP>Max -Alarm

SGC Turbine Valves

Alarm Only

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10MAD11 /12 CY021 / 22(mm/s) •Alarm Casing > 9.3 Vibrations MAD &Bearing MKD •Alarm >•Trip 9.4 > 11.8 •If Deviation between two Transmitters > •Trip > 14.9 •If Deviation 1 then FAULTtwo Transmitters > between 1 then FAULT Relative Shaft-Brg Vib. Shaft Axial Position 2v3 + 0.5 mm ALRAM + 1 mm ST Prot TRIP Fault If Deviation between 2 transmitters > 0.09 mm

If Speed > 45 Hz and Value > 83 μm =Alarm And Value > 130μm =High

If all channels of any measurement become faulty then ST TRIP

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TURBINE JOURNAL / THRUST BRGS

GENERATOR BRGS

1v3 > 90 Deg C -ALARM 2v3 > 130 Deg C –TRIP

If all channels of any measurement become faulty then ST TRIP

1v3 > 100 Deg C -ALARM

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2v3 > 110 Deg C –TRIP

DRAIN Valve before ESV MAL09/10AA011 Open-OR condition 1)SGC ST Step 7 2)Speed > 47.5 Hz & Steam Superheat Value < 20 o K 3)Superheat Value – Fault & Load < 8 MW Close- OR condition 1)SGC ST Step 19 or Step 55 2)Speed > 47.5 Hz & SH > 50 o K 3) SH Fault & load > 40 MW DRAIN Valve before CV MAL11/12AA011 Open-OR condition 1)SGC ST Step 5 2)SGC ST Step 18 & Upper Temp Margin Value > 5 K 3)ESV & CV are Close & Speed > 47.5 Hz for 5 Hrs Close-OR condition DRAIN Valve after CV 1)SGC ST Step 14/26/55 DRAIN Valve Turbine casing MAL15AA011 2)Speed > 47.5 Hz & ESV Opened Open-ORMAL11AA011 condition & CV Position Not Closed Open-OR condition 1) SH HPS Steam - Inner casing OK Level & <1)20 K drain LPS Turb Mon > Max1 2) ESV or 2 Opened SH ahead 2) TM HPS1Groove < 440 & ºC & MS Load < 8 MW Turbine ≤ 10 K Close-OR condition Close-OR condition 1) SGC Step 1) SGC STST Step 55 55 2) (Level drain LPS Turb Mon OK > Max1 OR 2) SH HPS Steam - Inner casing 1 or 2 Opened & SH MS ahead & > 50(ESV K K))º C Negated 3) TM HPSTurbine Groove≤>10 450 & Load + 30 sec > 8 MW

GSE System If > Max – Both the exhausters Prot OFF GSE SLC Auto ON in SGC ST Step 17 & Auto OFF in Step 55

IF Level drain LPS Turb Mon 10MAL22FL001 > Max2 DRAIN Valve Turbine casing MAL11AA011 will Protection53 Open and Block AP

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Gland Steam Extraction Points

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GLAND STEAM EXHAUSTER

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Thank You!

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